Abstract: Formation of carbonate fractured-vuggy reservoirs is controlled by palaeogeomorphology,tectonic movement and karstification.The main storage spaces are large-scale caves,small-scale dissolved pores and multi-scale fractures with different geometry.Because of complicated genetic mechanisms and highly discrete,traditional continuum reservoir characterization methods are difficult to apply directly.Based on the recognition and description of fractured-vuggy reservoir,we use the classification characterization method to characterize various reservoirs.Guided by karst genetic mechanisms and outcrops studies,in combination with seismic qualitative forecast and quantitative inversion results,we simulate wea-thering karst caves and faults-controlled caves using sequential indicator and the object-based method respectively.We use the method of collaborative sequential indicator simulation to establish the distribution model of the small scale dissolution pore.Based on the seismic information,we establish the multi-scale discrete fracturing network using the artificial interpretation,ant tracking and random simulation methods.Based on karst genetic mechanisms,we construct fusion principle for different types of reservoirs,and thus effectively integrated different types of reservoirs.The results show that the idea of the classification and characterization method can effectively describe the strong heterogeneity of S80 unit.Based on the model,we can refine the reserve classification in different the reservoir pay sections,evaluate the new well design,identify the target area,and apply it to the numerical simulation of reservoirs.The method lays the geological foundation to guide discovery of remaining oil potential,and modification of development plan.

Key words: discrete modeling, fractured-vuggy reservoir body, carbonate reservoir, Ordovician, Tahe oilfield, Tarim Basin